Trait-situation interactions are the latest and perhaps most realistic issues in the study of personality and its behavioral consequences. Owing to its relatively new entry into the realm of personality research, the study of interactionism has not benefited from experimental designs which directly address the extent to which the trait is influenced by the situation and vice versa. Rather, investigators have tended to simply answer questions related to which traits are and are not consistent across situations for individuals. Such an approach, while giving some data on how traits and situations jointly influence behavior, does not scientifically examine interactions per se. This study proposes to place trait-situation interactions within the framework of Henry A. Murray's theory of personality and to directly confront the issue of what situational structures of persons (derived from Murray's press) are related to what trait structures of persons (derived from Murray's needs). Furthermore, the research will test the ability of nontraditional methods of personality assessment (multipoint bipolar scales and Thurstone-type scales) to measure individual differences in the selected needs. Press structures will first be obtained by a factor analysis of the ratings of the importance of a series of situations or press. Several different measures of selected needs will then be administered to individuals who will also provide ratings of press importance. Using the results of the previous factor analysis, press factor scores for these individuals will be obtained and used to identify the separate press groupings of persons. Finally, a factor analysis for each group separately will serve as a basis for relating unique patterns of needs to each press structure.